Electrically conductive film

ABSTRACT

An electrically conductive film has an electrically conductive layer on at least one side, which is a thermoplastic resin film in which the electrically conductive layer contains a carbon nanotube (A), a carbon nanotube dispersant (B) and a binder resin (C), the total of contents of (A), (B) and (C) in the electrically conductive layer is 90% by weight or more relative to the entire electrically conductive layer, and weight rates of (A), (B) and (C) satisfy the following, and a weight ratio of (B) and (A) ((B)/(A)) is 0.5 or more and 15.0 or less:
         (A) 1.0 to 40.0% by weight,   (B) 0.5 to 90.0% by weight, and   (C) 4.0 to 98.5% by weight   (provided that the total of contents of (A), (B) and (C) is let to be 100% by weight).

RELATED APPLICATIONS

This is a divisional application of U.S. application Ser. No. 12/678,170filed Mar. 15, 2010, which is a §371 of International Application No.PCT/JP2008/064268, with an international filing date of Aug. 8, 2008 (WO2009/041170 A1, published Apr. 2, 2009), which is based on JapanesePatent Application Nos. 2007-253719, filed Sep. 28, 2007, and2008-057572, filed Mar. 7, 2008, the subject matter of which isincorporated by reference.

TECHNICAL FIELD

This disclosure relates to an electrically conductive film using acarbon nanotube (hereinafter, abbreviated as a CNT) and, moreparticularly, to an electrically conductive film having an electricallyconductive layer, which can be manufactured by applying a CNT dispersionto a thermoplastic resin film as a substrate.

BACKGROUND

In recent years, using materials containing CNTs, materials havingfunctions such as an anti-electrostatic property, electricalconductivity, thermal conductivity and an electromagnetic wave shieldingproperty have been actively developed. For example, many studiesregarding a composite material having functions such as ananti-electrostatic property, electrical conductivity, thermalconductivity and an electromagnetic wave shielding property, and alaminate obtained by laminating these composite materials have beenperformed by using a polymer such as a polyamide, a polyester, apolyether or a polyimide, or an inorganic material such as glass or aceramic material as a matrix, and dispersing a CNT in the matrix.

As a CNT, there are a monolayer nanotube consisting of one graphenelayer, and a multilayer nanotube constructed of a plurality of graphenelayers. To utilize structural properties such as an extremely greataspect ratio and an extremely small diameter, and to manifesttransparency, electrical conductivity and other physical properties, itis necessary to finely disperse CNTs at an extremely high level,ultimately, to monodisperse CNTs. Particularly, when the compositematerial is laminated on other materials, it is necessary to finelydisperse a CNT in the composite material at a necessary minimum amountand at a high level so as not to give any influence on opticalproperties of the other materials.

In addition, to utilize properties of a CNT by coating, it is necessaryto form a network structure of a finely dispersed CNT on a substrate.Thereby, it is expected that high transparency and electricalconductivity can be manifested even when the use amount of a CNT isextremely small.

Previously, processes for manufacturing an electrically conductive filmby a method of applying an electrically conductive layer containing aCNT on a film, or the like, have been known. However, in these knowntechniques, for example, in JP-A No. 2002-67209, a coated film thicknessshould become extremely great to impart desired electrical conductivity,neglecting processability and transparency as an electrically conductivesubstrate. In addition, in JP-A No, 2004-195678, a conjugatedpolymer-based electrically conductive polymer is used as a binder resinto maintain electrical conductivity of a CNT in an electricallyconductive layer, but an electrically conductive property which isoriginally possessed by a CNT is not utilized, and a resistance value asan electrically conductive film is extremely high. In JP-A No.2007-112133, a production process of an electrically conductive film iscomplicated to exert an electrically conductive property of a CNT, andthere is a problem in productivity and economy. Also in Japanese PatentNo. 3665969, to improve an adhesion property between an electricallyconductive layer and a substrate, a CNT is applied and, thereafter, theproduct is overcoated with a binder resin, and there is a problem inproductivity and economy as in JP-A No. 2007-112133. In addition, sincean organic solvent is used as a solvent in the four patent documentsshown herein, it cannot be said to be optimal also in respect ofenvironmental load. Further, for use as an electrostatic film or atransparent electrically conductive film as an electrically conductivelayer containing a CNT, solvent resistance and abrasion resistance of anelectrical conductive layer are important, but these properties are notreferred to in the four patent documents, and there is a fear ofdeficiency in solvent resistance and abrasion resistance.

Also, a CNT has been dispersed in a matrix or a resin to manufacture alaminate in which a CNT is finely dispersed. However, the dispersedstate of a CNT is not necessarily good and, in lamination by previouscoating, it was difficult to manifest properties inherent to a CNT sincea binder resin hinders electrical conductivity of a CNT, or a CNT causesaggregation in a drying step. In addition, abrasion resistance andsolvent resistance were not sufficient.

It could therefore be helpful to provide an electrically conductive filmexcellent in transparency, electrical conductivity, abrasion resistance,and solvent resistance, and having a coated film (electricallyconductive layer) in which a CNT is finely dispersed, at a lower costthan the previous manufacturing cost.

SUMMARY

We thus provide:

-   -   (1) An electrically conductive film having an electrically        conductive layer on at least one side, which is a thermoplastic        resin film in which the electrically conductive layer contains a        carbon nanotube (A), a carbon nanotube dispersant (B) and a        binder resin (C), the total of contents of (A), (B) including        carboxy methylcellulose sodium and (C) in the electrically        conductive layer is 90% by weight or more relative to the entire        electrically conductive layer, weight rates of (A), (B) and (C)        satisfy the following, and a weight ratio of (B) and (A)        ((B)/(A)) is 0.5 or more and 15.0 or less:        -   (A) 1.0 to 40.0% by weight        -   (B) 0.5 to 90.0% by weight        -   (C) 4.0 to 98.5% by weight    -   (provided that the total of contents of (A), (B) and (C) is let        to be 100% by weight).    -   (2) A process of producing the electrically conductive film of        (1), including applying a carbon nanotube dispersion containing        a carbon nanotube (A), a carbon nanotube dispersant (B), a        binder resin (C) and a solvent (D) to at least one side of a        thermoplastic film before completion of crystal orientation,        thereafter stretching the thermoplastic film by a monoaxial or        biaxial stretching method, and heat-treating the film at a        temperature higher than the boiling point of the electrically        conductive layer solvent to complete crystal orientation of the        thermoplastic resin film.

Since the electrically conductive film is excellent in electricalconductivity, transparency, solvent resistance, and abrasion resistance,it can be suitably used for a variety of purposes requiring theseproperties. In addition, since the film can be obtained by a simplerprocess as compared with the previous process, the film can bemanufactured at a lower cost.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing one example of a cross-section of anelectrically conductive film.

FIG. 2 is a photograph showing one example of surface observation, withan electron microscope, if the electrically conductive film.

DESCRIPTION OF THE REFERENCE NUMERALS

1. Thermoplastic resin film (substrate film)

2. Electrically conductive layer

DETAILED DESCRIPTION

The electrically conductive film will be explained in detail below.

The electrically conductive film is a film having an electricallyconductive layer on at least one side of a thermoplastic resin film, andit is necessary that the electrically conductive layer contains a CNT(A), a carbon nanotube dispersant (B), and a binder resin (C).

(1) Thermoplastic Resin Film

The thermoplastic resin film is a generic name of films using athermoplastic resin, which are melted or softened by heat, without anylimitation. Examples of the thermoplastic resin include polyolefinresins such as a polyester resin, a polypropylene resin, and apolyethylene film, a polylactic acid resin, a polycarbonate resin,acrylic resins such as a polymethacrylate resin and a polystyrene resin,polyamide resins such as a nylon resin, a polyvinyl chloride resin, apolyurethane resin, a fluorine resin, and a polyphenylene resin. Thethermoplastic resin used in the thermoplastic resin film may be amonopolymer or a copolymerized polymer. In addition, a plurality ofresins may be used.

Representative examples of the thermoplastic resin film using thesethermoplastic resins include a polyester film, polyolefin films such asa polypropylene film and a polyethylene film, a polylactic acid film, apolycarbonate film, acrylic-based films such as a polymethacrylate filmand a polystyrene film, a polyamide film such as nylon, a polyvinylchloride film, a polyurethane film, a fluorine-based film, and apolyphenylene sulfide film.

Among them, from the view point of a mechanical property, dimensionalstability and transparency, a polyester film, a polypropylene film, anda polyamide film are preferable and, further, a polyester film isparticularly preferable from the view point of mechanical strength and ageneral-use property.

In the following, a polyester resin constituting a polyester film whichis particularly suitably used as the thermoplastic resin film will beexplained in detail.

First, the polyester is a generic name of polymers having an ester bondas a main bonding chain of a main chain, and a polyester having, as amain constituent component, at least one kind of constituent componentselected from ethylene terephthalate, propylene terephthalate,ethylene-2,6-naphthalate, butylene terephthalate,propylene-2,6-naphthalate,ethylene-α,β-bis(2-chlorophenoxy)ethane-4,4′-dicarboxylate, and the likecan be preferably used. Only one kind of these constituent componentsmay be used, or two or more kinds may be used together and, among them,ethylene terephthalate is particularly preferably used whencomprehensively determining quality and economy. That is, it ispreferable to use polyethylene terephthalate as the thermoplastic resinused for the thermoplastic resin film. In addition, when heat or ashrinking stress is made to act on the thermoplastic resin film,polyethylene-2,6-naphthalate excellent in heat resistance and rigidityis particularly preferable. In these polyesters, other dicarboxylic acidcomponents or diol components may be further contained partially,preferably at 20 mol % or less.

A limiting viscosity (as measured in o-chlorophenol at 25° C.) of thepolyester is in a range of preferably 0.4 to 1.2 dl/g, and morepreferably 0.5 to 0.8 dl/g.

It is preferable that a polyester film using the polyester has beenbiaxially oriented. The biaxially oriented polyester film generallyrefers to a polyester film obtained by stretching a polyester sheet orfilm in the unstretched state, each around 2.5 to 5-fold, in alongitudinal direction and a width direction orthogonal to thelongitudinal direction, and thereafter heat-treating the sheet or filmto complete crystal orientation, and which exhibits a biaxialorientation pattern by wide-angle X-ray diffraction. When thethermoplastic resin film has not been biaxially oriented, thermalstability, particularly, dimensional stability and mechanical strengthof the electrically conductive film are insufficient, and planarity ispoor, being not preferable.

In addition, various additives, for example, antioxidants, heatresistance stabilizers, weather resistance stabilizers, ultravioletabsorbing agents, organic easy sliding agents, pigments, dyes, organicor inorganic fine particles, fillers, antistatics, and nucleating agentsmay be added to the thermoplastic resin film to such an extent thatproperties thereof are not deteriorated.

The thickness of the thermoplastic resin film is not particularlylimited and is appropriately selected depending on a purpose and a kind.From the view point of mechanical strength and a handling property,usually the thickness is preferably 10 to 500 more preferably 38 to 250μm, and most preferably 75 to 150 μm. In addition, the thermoplasticresin film may be a composite film obtained by coextrusion, or a film inwhich the resulting films have been laminated by various methods.

(2) Carbon Nanotube (A)

A CNT is a genetic name of seamless (non-seam) tubes in which a graphenesheet having a honey comb structure composed only of carbon atoms isrounded into a cylinder, and a tube in which a graphene sheet issubstantially wound into one layer is referred to as a monolayer CNT, atube in which a graphene sheet is wound into two layers is referred toas a bilayer CNT, and a tube in which a graphene sheet is wound intomultiple layers of three or more layers is referred to as a multilayerCNT. It is preferable that the CNT (A) is any of a straight orbending-shaped monolayer CNT, a straight or bending-shaped bilayer CNT,and a straight or bending-shaped multilayer CNT or a combinationthereof.

In addition, the honey comb structure refers to a network structuremainly composed of a 6-membered ring, and may have a cyclic structureother than a 6-membered ring, such as a 5-membered ring or a 7-memberedring, on a bending part of a tube or a closing part of a cross-section,from the view point of the structure of the CNT.

Further, among these CNTs, from the view point of electricalconductivity, it is preferable to use a straight and/or bending-shapedbilayer CNT, and it is more preferable to use a straight bilayer CNT.The bilayer CNT is excellent in dispersibility in a solvent, durability,and the manufacturing cost while having excellent electricalconductivity equivalent to that of a monolayer CNT. Further, when alayer on an outer side is chemically modified to impart a functionalgroup, or a solvent having high affinity is adsorbed on a surface, thelayer on the outer side can be partially destroyed, or electricalconductivity derived from the layer on the outer side can be reduced,but since a layer on an inner side remains without beingtransubstantiated, affinity for a solvent or a resin can be impartedwhile maintaining properties (particularly, electrical conductivity) asa CNT. In addition, the bilayer CNT has, on one hand, equivalentdispersibility and manufacturing cost, and has, on the other hand, muchhigher electrical conductivity as compared with the multilayer CNT.

In addition, it is preferable that a CNT used has a diameter of 1 nm ormore. In addition, the diameter of a CNT is preferably 50 nm or less,and more preferably 10 nm or less. When the diameter is more than 50 nm,a CNT comes to have a multilayer structure of three or more layers, anelectrically conducting route is diverged between layers, and electricalconductivity is reduced in some cases, being not preferable. Inaddition, in this case, when one tries to manifest electricalconductivity equivalent to that of a CNT having a diameter of 50 nm orless, a large amount of CNTs are required, and not only transparency ofthe electrically conductive film is extremely deteriorated, but alsosufficient electrical conductivity cannot be attained in some cases evenif the amount is increased without any limitation. Further, when thediameter of a CNT is 50 nm or more, an adhesion property and abrasionresistance of the electrically conductive layer are deteriorated in somecases. In addition, it is difficult to produce a CNT having a diameterof less than 1 mm.

It is preferable that the aspect ratio of a CNT used is 100 or more. Inaddition, it is preferable that the aspect ratio of a CNT is 5000 orless. Therefore, it is preferable that a CNT has a diameter of 50 nm orless or an aspect ratio of 100 or more. More preferably, the diameter is50 nm or less, and the aspect ratio is 100 or more. Further preferably,the diameter of a CNT used is 1 nm or more and 50 nm or less, the aspectratio is 100 or more and 5000 or less and, particularly preferably, thediameter of a CNT used is 1 nm or more and 10 nm or less, and the aspectratio is 100 or more and 5000 or less. By making the diameter and theaspect ratio of a CNT in the aforementioned range, a CNT is excellent iselectrical conductivity and, by using a dispersant or the like, itbecomes possible to disperse a CNT in a solvent such as water.

In addition, the aspect ratio is a length (nm) of a carbon tube dividedby a diameter (nm) of a carbon tube (length of carbon tube (nm)/diameter(nm) of carbon tube). A CNT having such properties is obtained by aknown process such as a chemical deposition method, a catalytic vaporgrowing method, an arc discharging method, or a laser vaporizing method.Upon manufacturing of a CNT, fullerene, graphite, or amorphous carbon issimultaneously generated as a byproduct, and a catalyst metal such asnickel, iron, cobalt, or yttrium remains, therefore, it is preferable toremove these impurities to purify a CNT. For removing impurities, anultrasonic dispersing treatment together with an acid treatment withnitric acid or sulfuric acid is effective, and it is further preferableto jointly use separation with a filter for improving purity.

The monolayer CNT or the bilayer CNT is generally thinner than themultilayer CNT and, when uniformly dispersed, a larger number ofelectrically conducting routes per unit volume can be ensured andelectrical conductivity is high, while a semiconducting CNT may begenerated as a byproduct in a large amount depending on a manufacturingprocess and, in that case, it becomes necessary to selectively produceor select an electrically conductive CNT. The multilayer CNT generallyexhibits electrical conductivity but when the number of layers is toolarge, the number of electrically conducting routes per unit weight isreduced. Therefore, even when the multilayer CNT is used, the diameterof the CNT is preferably 50 nm or less, more preferably 20 nm or less,and further preferably 10 nm or less. In addition, when the monolayerCNT or the bilayer CNT is used, it is preferable from the view point ofelectrical conductivity that the diameter is 20 nm or less, and furtherpreferably 10 nm or less, in the light of its structure.

It is preferable that the aspect ratio of the CNT is 100 or more and5000 or less and, by making the aspect ratio 100 or more, electricalconductivity of the electrically conductive layer can be enhanced. Thisis because, when an in-line coating method described later is used information of the electrical conductive layer, the CNT is moderatelyloosened in a stretching step, an electrically conducting route betweenCNTs is not cut, and a network ensuring a sufficient gap between CNTscan be formed. When such a network structure is formed, a goodelectrically conductive property can be manifested while a transparencydegree of a film is enhanced.

Therefore, it is preferable to use a CNT having an aspect ratio of 100or more as the CNT, and the aspect ratio is more preferably 500 or more,and further preferably 1000 or more. In addition, by making the aspectratio 5000 or less, it becomes possible to stably disperse the CNT in asolvent.

It is necessary that a compositional weight rate of the CNT (A) in theelectrically conductive layer (the total of contents of (A), (B) and (C)in the electrically conductive layer is let to be 100% by weight) is1.0% by weight or more and 40.0% by weight or less. More preferably, therate is 6.0% by weight or more and 12.0% by weight or less, and furtherpreferably the rate is 8.0% by weight or more and 10.0% by weight orless. In addition, in purposes requiring high electrical conductivity,it is preferable that the rate is 30.0% by weight or more and 40.0% byweight or less. By making the rate 1.0% by weight or more, it becomeseasy to make the surface specific resistance value of the electricallyconductive film 1.0×10¹⁰Ω/□ or less. In addition, by making the rate40.0% by weight or less, it becomes easy to make a total lighttransmittance of the electrically conductive film 70% or more. Inaddition, a binder resin described later can be sufficiently containedin the electrically conductive layer, and the CNT can be immobilized onthe thermoplastic resin film more firmly. Thereby, abrasion resistanceand solvent resistance of the electrically conductive layer can beimproved.

(3) Carbon Nanotube Dispersant (B)

To finely disperse the CNT (A) in the electrically conductive layeruniformly, it is necessary to use a carbon nanotube dispersant (B). Thekind of the carbon nanotube dispersant is not particularly limited, butany one of a polystyrenesulfonate salt, a polyvinylpyrrolidone-basedpolymer, water-soluble cellulose, and a water-soluble cellulosederivative, or a combination thereof is preferable from the view pointof compatibility with a binder resin (C) described later, abrasionresistance and solvent resistance of the electrically conductive layer,and dispersing of the CNT.

Representative examples of the polystyrenesulfonate salt include sodiumpolystyrene-sulfonate and calcium polystyrenesulfonate.

Representative examples of the polyvinylpyrrolidone-based polymerinclude polyvinylpyrrolidone.

Representative examples of the water-soluble cellulose includehydroxycellulose and hydroxyalkylcellulose. Hydroxyalkylcellulose iscellulose in which a hydroxy group of a glucopyranose monomerconstituting a skeleton of cellulose is replaced with a hydroxyalkylgroup (when a glucopyranose monomer has a plurality of hydroxy groups,it is sufficient that at least one hydroxy group is replaced with ahydroxyalkyl group). Preferably, hydroxypropyl-methylcellulose andhydroxyethycellulose can be exemplified.

In addition, representative examples of the water-soluble cellulosederivative include a metal salt of carboxycellulose. Carboxycellulose iscellulose in which a hydroxy group of a glucopyranose monomerconstituting a skeleton of cellulose is replaced with a carboxy group(when a glucopyranose monomer has a plurality of hydroxy groups, it issufficient that at least one hydroxy group is replaced with a carboxygroup). A carboxy group is a concept including not only a carboxy groupin a narrow sense, but also a carboxyalkyl group. By makingcarboxycellulose into a metal salt, water-solubility can be dramaticallyenhanced, and a CNT dispersing ability can be enhanced. In addition,among metal salts of carboxycellulose, from the view point of goodwater-solubility, a metal salt of carboxyalkylcellulose is preferable,and carboxymethylcellulose sodium and carboxymethylcellulose calciumwhich are inexpensive and are widely used industrially are morepreferably exemplified. Particularly preferable iscarboxy-methylcellulose sodium.

In addition, as the CNT dispersant, two or more CNT dispersants may beused in combination. In addition, although details of the reason whythese substances can be suitably used as a dispersant are unknown, wepresume a dispersing mechanism as follows. That is, since the substanceshave a cyclic structure having a molecular structure consisting ofcarbon, it is presumed that affinity such as surface energy and/or ahydrophobic interaction with a CNT having a structure in which aconjugated structure consisting of carbon is extended, is very high. Inaddition, since the substances are easily soluble in water which is asuitable solvent for a CNT dispersant, and uniformly diffuse in thevicinity of the CNT in a solvent, it is presumed that aggregation due toaffinity between CNTs is inhibited. For this reason, it is presumedthat, by using the substances, a stable and finely dispersed CNTdispersion can be made.

It is preferable to use at least water-soluble cellulose or awater-soluble cellulose derivative as the CNT dispersant. Particularlypreferably, at least a water-soluble cellulose derivative is used. Byusing these substances, dispersibility of the CNT can be furtherimproved, and abrasion resistance, adhesion resistance and solventresistance of the electrically conductive layer can be improved.

In addition, it is necessary that a compositional weight rate of the CNTdispersant (B) in the electrically conductive layer (the total ofcontents of (A), (B) and (C) in the electrically conductive layer is letto be 100% by weight) is 0.5% by weight or more and 90.0% by weight orless. By making a compositional weight rate of the CNT dispersant in theelectrically conductive layer 0.5% by weight or more, it becomespossible to finely disperse the CNT. In addition, by making the rate90.0% by weight or less, a binder resin described later can besufficiently contained in the electrically conductive layer, and afirmer electrically conductive layer can be formed. Thereby, abrasionresistance and solvent resistance of the electrically conductive layercan be improved. In addition, the lower limit value of the compositionalweight rate of the CNT dispersant in the electrically conductive layeris preferably 3.0% by weight or more, and more preferably 4.0% by weightor more. On the other hand, the upper limit value of the compositionalweight rate of the CNT dispersant in the electrically conductive layeris preferably 75.0% by weight or less, more preferably 60.0% by weightor less, further preferably 48% by weight or less, and particularlypreferably 20.0% by weight or less.

Therefore, the compositional weight rate of the CNT dispersant (B) inthe electrically conductive layer is preferably 0.5% by weight or moreand 75.0% by weight or less, more preferably 0.5% by weight or more and60.0% by weight or less, further preferably 3.0% by weight or more and48.0% by weight or less, and particularly preferably 4.0% by weight ormore and 20.0% by weight or less. In addition, in purposes requiringhigh electrical conductivity, since the compositional weight rate of theCNT is preferably 30.0% by weight or more and 40.0% by weight or less,it is preferable that the CNT dispersant is contained at 15.0% by weightor more and 56.0% by weight or less depending on the amount of the CNT.

In addition, it is necessary that a weight ratio of the CNT dispersant(B) and the CNT (A) in the electrically conductive layer (CNT dispersant(B)/CNT (A)) is 0.5 or more and 15.0 or less, preferably 0.5 or more and10.0 or less, more preferably 0.5 or more and 5.0 or less, furtherpreferably 0.5 or more and 4.0 or less, and particularly preferably 0.5or more and 2.0 or less. In addition, in purposes requiring highelectrical conductivity, it is preferable that the weight ratio is 0.5or more and 1.9 or less depending on the compositional weight rates ofthe CNT and the CNT dispersant. By making the weight ratio of (B)/(A)0.5 or more, upon mixing with a binder resin, a CNT dispersion can bemade stably without causing aggregation of a CNT and, by making theweight ratio 15.0 or less, a binder resin described later can besufficiently contained in the electrically conductive layer, and afirmer electrically conductive layer can be formed. Thereby, abrasionresistance and solvent resistance of the electrically conductive layercan be improved.

(4) Binder Resin (C)

The binder resin is not particularly limited, and any of a thermoplasticresin, a thermosetting resin, and an ultraviolet curing resin can beused. For example, it is preferable to use an acrylic resin, a polyesterresin, a urethane resin, a melamine resin, a phenol resin, an epoxyresin, a polyamide resin, a urea resin, an unsaturated polyester resinor the like, or the aforementioned resins mixed with an additive.Particularly, either one of a polyester resin and a melamine resin, or acombination thereof is preferable. By using either one of a polyesterresin and a melamine resin, or a combination thereof, transparency,solvent resistance, and abrasion resistance can be easily impartedwithout deterioration of dispersibility of a CNT.

As the additive to be mixed with the binder resin, an antioxidant, aheat resistance stabilizer, a weather resistance stabilizer, anultraviolet absorbing agent, an organic easy sliding agent such as anatural or petroleum wax, a pigment, a dye, an organic or inorganic fineparticle, a filler, and a nucleating agent may be added to such anextent that properties of the resin and dispersibility of a CNT are notdeteriorated. A role of the binder resin is to fix a CNT on the film,and to impart properties required for the electrically conductive filmsuch as transparency and a hard coating property, and it is preferablethat an electrically conductive layer compositional rate (% by weight ofa binder resin, letting the total of contents of (A), (B) and (C) in theelectrically conductive layer to be 100% by weight) is made to be asgreat as possible in such a range that electrical conductivity of a CNTis not impaired. This is because, when the electrically conductive layercompositional rate is great, dropping of a CNT from the electricallyconductive layer can be easily prevented and, when a transparent resinis used for a binder, transparency of the electrically conductive filmcan be easily imparted.

Therefore, it is necessary that a content of the binder resin (C) in theelectrically conductive layer as expressed by a compositional weightrate in the electrically conductive layer (the total of contents of (A),(B) and (C) in the electrically conductive layer is let to be 100% byweight) is 4.0% by weight or more and 98.5% by weight or less. Thecontent is preferably 5.0% by weight or more and 98.5% by weight orless. By making the content 4.0% by weight or more, dropping of a CNTfrom the electrically conductive layer can be prevented and, when atransparent resin is used as a binder resin, high transparency can beimparted to the electrically conductive film. On the other hand, bymaking the content 98.5% by weight of less, electrical conductivity ofthe electrically conductive layer can be more enhanced. In addition, thelower limit value of the compositional weight rate of the binder resin(C) in the electrically conductive layer is preferably 20.0% by weightor more, more preferably 35.0% by weight or more, further preferably40.0% by weight or more, and particularly preferably 70.0% by weight ormore. On the other hand, the upper limit value of the compositionalweight rate of the binder resin (C) in the electrically conductive layeris preferably 91.0% by weight or less, and more preferably 88.0% byweight or less.

Therefore, the compositional weight rate of the binder resin (C) in theelectrically conductive layer is preferably 20.0% by weight or more and98.5% by weight or less, more preferably 35.0% by weight or more and98.5% by weight or less, further preferably 40.0% by weight or more and91.0% by weight or less, and particularly preferably 70.0% by weight ormore and 88.0% by weight or less. In addition, in purposes requiringhigh electrical conductivity, since it is preferable that thecompositional weight rate of a CNT is 30.0% by weight or more and 40.0%by weight or less, and the compositional weight rate of the CNTdispersant is 15.0% by weight or more and 56.0% by weight or less, it ispreferable that the compositional weight rate of the binder resin is4.0% by weight or more and 55.0% by weight or less in order that solventresistance and abrasion resistance are not reduced.

(5) Electrically Conductive Layer

As described above, it is necessary that the electrically conductivelayer contains the CNT (A), the CNT dispersant (B) and the binder resin(C) and, further, it is necessary that the total of contents of (A), (B)and (C) in the electrically conductive layer is 90% by weight or morerelative to the entire electrically conductive layer. By making thetotal of contents of (A), (B) and (C) 90% by weight or more relative tothe entire electrically conductive layer, the effect can be exerted. Itis preferable that the total of contents of (A), (B) and (C) in theelectrically conductive layer is 95% by weight or more relative to theentire electrically conductive layer, and it is more preferable that theelectrically conductive layer consists of (A), (B) and (C).

On the other hand, when the total is less than 10% by weight relative tothe entire electrically conductive layer, other components may becontained in the electrically conductive layer to such an extent thatproperties of the binder resin and dispersibility of the CNT are notdeteriorated. For example, to enhance wettability of a carbon nanotubedispersion onto a thermoplastic resin film, an arbitrary surfactant maybe contained and, to impart an easy sliding property of the electricallyconductive film, an organic easy sliding agent such as a natural orpetroleum wax, a releasing agent and a particle may be contained.

(6) Method of Forming Electrically Conductive Layer

The electrically conductive layer can be formed by applying a carbonnanotube dispersion containing the aforementioned CNT (A), CNTdispersant (B) and binder resin (C) and, optionally, a solvent (D) to athermoplastic resin film, and drying the solvent (D) to cure the binderresin (B) (FIG. 1). A specific process for preparing a CNT dispersionwill be described later.

As the solvent (D), an aqueous solvent (d) or an organic solvent (d′)can be used, and preferable is the aqueous solvent (d). This is because,by using an aqueous solvent, rapid evaporation of the solvent in adrying step can be suppressed, and not only a uniform electricallyconductive layer can be formed, but also the aqueous solvent isexcellent in respect of environmental load.

The aqueous solvent (d) refers to water, or a solvent in which water,and an organic solvent soluble in water including an alcohol such asmethanol, ethanol, isopropyl alcohol or butanol, a ketone such asacetone or methyl ethyl ketone, or a glycol such as ethylene glycol,diethylene glycol or propylene glycol is mixed at an arbitrary ratio.

In addition, the organic solvent (d′) refers to a solvent other than theaqueous solvent, and refers to a solvent not substantially containingwater. The kind of the organic solvent is not particularly limited, andexamples thereof include alcohols such as methanol, ethanol, isopropylalcohol and butanol, ketones such as acetone and methyl ethyl ketone,glycols such as ethylene glycol, diethylene glycol and propylene glycol,aromatic solvents such as benzene and toluene, and hydrocarbons such ashexane.

As a method of applying the CNT dispersion to a film, either of anin-line coating method or an off coating method can be used, butpreferable is the in-line coating method.

The in-line coating method is a method of performing application in aproduction process of a thermoplastic resin film. Specifically, itrefers to a method of performing application at an arbitrary stage frommelt extrusion of a thermoplastic resin to a heat treatment and windingup after biaxial stretching. Usually, the dispersion is applied to anyfilm of an unstretched (unoriented) thermoplastic resin film in asubstantially amorphous state, obtained by melt extrusion and rapidcooling thereafter (A film), a monoaxially stretched (monoaxiallyoriented) thermoplastic resin film stretched in a longitudinal directionthereafter (B film), or a biaxially stretched (biaxially oriented)thermoplastic resin film before a heat treatment, which has been furtherstretched in a width direction (C film).

It is preferable to adopt a method of applying a CNT dispersion to anythermoplastic resin film of the A film, the B film and the C film beforecompletion of crystal orientation, thereafter stretching thethermoplastic resin film monoaxially or biaxially, and heat-treating thefilm at a temperature higher than the boiling point of a solvent tocomplete crystal orientation of the thermoplastic resin film, and, atthe same time, providing an electrically conductive layer. According tothe method, since making of the thermoplastic resin film, andapplication and drying of the CNT dispersion (i.e., formation of anelectrically conductive layer) can be performed simultaneously, there isa merit in terms of the production cost. In addition, it is easy toreduce the thickness of the electrically conductive layer sincestretching is performed after application. In addition, by making thetemperature of the heat treatment performed after application atemperature higher than the boiling point of a solvent, the binder resincan be effectively solidified and cured, and abrasion resistance andsolvent resistance of the electrically conductive layer can be improved.Further, by the step of stretching the thermoplastic resin film, the CNTin the CNT dispersion is moderately loosened and an electricallyconductive film excellent in transparency and electrical conductivitycan be obtained.

Inter alia, a method of applying the CNT dispersion to a film (B film)which has been monoaxially stretched in a longitudinal direction,thereafter stretching the film in a width direction, and heat-treatingthe film is excellent. The reason is as follows: since the number ofstretching steps is smaller by one time as compared with a method ofapplying the CNT dispersion to an unstretched film and thereafterperforming biaxial stretching, cutting of an electrically conductingroute between CNTs due to stretching hardly occurs, and an electricallyconductive layer excellent in electrical conductivity can be formed.

On the other hand, the off-line coating method is a method of applying aCNT dispersion to a film obtained after stretching the A filmmonoaxially or biaxially and heat-treating the film to complete crystalorientation of a thermoplastic resin film, or to the A film, in a stepseparate from a step of making a film.

It is preferable that the electrically conductive layer is provided bythe in-line coating method for the reason of the aforementioned variousadvantages.

Therefore, the best method of forming an electrically conductive layeris a method of applying a CNT dispersion using an aqueous solvent (d) asthe solvent (D) to a thermoplastic resin film using the in-line coatingmethod, and drying the dispersion. In addition, more preferable is amethod of in-line coating a B film with a CNT dispersion coatingsolution after monoaxial stretching.

(7) Preparation of CNT Dispersion

A method of preparing a CNT dispersion in a case where the aqueoussolvent (d) is used as the solvent (D) will be explained below, and aCNT dispersion in a case where an organic solvent is as the solvent canbe made by a similar method.

For preparing the CNT dispersion, it is preferable that, first, a CNTwater dispersion in which a CNT is dispersed in a solvent is prepared.As a method of making the CNT water dispersion, there are:

-   -   (I) a method of dissolving a CNT dispersant in water as a        solvent, adding a CNT thereto, and mixing and stirring this to        prepare a CNT water dispersion,    -   (II) a method of preliminarily dispersing a CNT in water by        ultrasonic dispersing or the like in advance, thereafter adding        a CNT dispersant thereto, followed by mixing and stirring this        to prepare a CNT water dispersion, and    -   (III) a method of placing a CNT and a CNT dispersant in water,        followed by mixing and stirring this to prepare a CNT water        dispersion.

Any methods may be used alone or in combination. In addition, in thestirring method, a magnetic stirrer or a stirring wing may be used, orultrasonic irradiation or vibration dispersing can be performed. Amongthem, the method (III) is preferable in that unnecessary aggregation ofa CNT generated by contact with water is prevented, and a CNT can beefficiently dispersed in water.

Then, it is preferable that a binder resin is added to the CNT waterdispersion, and mixing and stirring are performed using the methods (I)to (III), thereby, a CNT dispersion is made. In addition, upon additionof a binder resin, if necessary, the aforementioned various additivesmay be added to such an extent that the binder resin properties anddispersibility of a CNT are not deteriorated.

(8) Application System

As an application system, the known application systems, for example, anarbitrary system such as a bar coating method, a reverse coating method,a gravure coating method, a dye coating method, or a blade coatingmethod can be used.

(9) Process for Producing Electrically Conductive Film

Then, regarding a process for producing the electrically conductivefilm, an example of a case using a polyethylene terephthalate(hereinafter, abbreviated as PET) film as the thermoplastic resin filmwill be explained, but the process is naturally not limited to this.

First, after PET pellets are sufficiently vacuum-dried, the pellets aresupplied to an extruder, melt-extruded into a sheet at about 280° C.,and cooled to solidify to prepare an unstretched (unoriented) PET film(A film). This film is stretched 2.5 to 5.0-fold in a longitudinaldirection with a roll heated to 80 to 120° C. to obtain a monoaxiallyoriented PET film (B film). To one side of this B film, the CNTdispersion prepared to have a predetermined concentration is applied.Thereupon, before application, a surface of the PET film to be coatedmay be subjected to a surface treatment such as a corona dischargetreatment. By performing a surface treatment such as a corona dischargetreatment, wettability of the CNT dispersion onto the PET film isimproved, and repellency of the CNT dispersion is prevented, thereby, auniform coating thickness can be attained.

After application, an end of the PET film is grasped with a clip, guidedto a heat treatment zone of 80 to 130° C. (pre-heating zone), and wateras a solvent for the electrically conductive layer is dried. Afterdrying, the film is stretched 1.1 to 5.0-fold in a width direction. Whena CNT is loosened in the stretching step in in-line coating, a networkensuring a sufficient gap between CNTs can be formed without cutting anelectrically conducting route between CNTs. Subsequently, the film isguided to a heat treatment zone of 160 to 240° C. (heat-fixing zone),and heat-treated for 1 to 30 seconds to complete crystal orientation.

In this heat-treating step (heat-fixing step), if necessary, 3 to 15% ofa relaxing treatment may be performed in a width direction or alongitudinal direction. The thus obtained film is a transparentelectrically conductive film of high electrical conductivity, fixed in astate where a CNT is finely dispersed in the electrically conductivelayer.

The thickness of the electrically conductive layer is preferably 2 nm ormore and 500 nm or less. When the thickness of the electricallyconductive layer is 2 nm or more, an electrically conductive film havinghigh electrical conductivity can be prepared and, when the thickness is500 nm or less, transparency can be maintained.

(10) Physical Properties of Electrically Conductive Film

The surface specific resistance value of the electrically conductivefilm is preferably 1.0×10¹⁰Ω/□ or less. When the surface specificresistance value is 1.0×10¹⁰Ω/□ or less, it is indicated that a CNT iswell dispersed, and a total light transmittance of 70% or more can beeasily attained while excellent electrical conductivity is possessed.The lower limit is not particularly limited, but from the electricallyconductive layer compositional weight rate, as a region where electricalconductivity of a CNT can be exerted, 1.0×10²Ω/□ is a limit value (lowerlimit).

Examples of a means to attain the aforementioned range of the surfacespecific resistance value of the electrically conductive film includeuse of a bilayer CNT as a CNT, and a compositional weight rate of theCNT (A) in an electrically conductive layer of 8.0% by weight or more(the total of contents of (A), (B) and (C) in the electricallyconductive layer is let to be 100% by weight).

In addition, it is preferable that, in the electrically conductive film,a surface resistance value B (Ω/□) of an electrically conductive layersurface after a rubbing treatment, and a surface resistance value A(Ω/□) of an electrically conductive layer surface before a rubbingtreatment satisfy the following equation. Details of the rubbingtreatment will be described later.

B/A≦10.0

Examples of an attainment means to satisfy the above relational equationof the surface specific resistance values A and B of the electricallyconductive film include use of a bilayer CNT as a CNT, and use of a CNThaving a diameter of 50 nm or less.

Further, in the electrically conductive film, it is preferable that thesurface resistance value A (Ω/□) of an electrically conductive layersurface is 1.0×10¹⁰Ω/□ or less, and the surface resistance value B (Ω/□)of an electrically conductive layer surface after a rubbing treatmentsatisfies B/A≦10.0.

Examples of a means to attain this include use of a bilayer CNT as aCNT, a compositional weight rate of the CNT (A) in the electricallyconductive layer (the total of contents of (A), (B) and (C) in theelectrically conductive layer is let to be 100% by weight) of 8.0% byweight or more, and use of a CNT having a diameter of 50 nm or less.

In addition, it is preferable that the electrically conductive film hasits total light transmittance of 70% or more. When the total lighttransmittance is 70% or more, from the view point of formation of anelectrically conductive layer containing a CNT, it is indicated that aCNT is well dispersed and, in addition, when an electrical propertyinherent to a CNT is utilized, sufficient electrical conductivity isobtained. Further, the film can be suitably used for purposes requiringtransparency, as purposes of the electrically conductive film. The upperlimit is not particularly limited, but in view of light reflection of afilm surface, a total light transmittance of 92% is the physical limitvalue (upper limit) when an electrically conductive layer is formed on athermoplastic resin film.

Examples of a means to attain the total light transmittance of theelectrically conductive film of 70% or more include use of a bilayer CNTas a CNT, use of a CNT having a diameter of 50 nm or less, and acompositional weight rate of the CNT (A) in the electrically conductivelayer (the total of contents of (A), (B) and (C) in the electricallyconductive layer is let to be 100% by weight) of 40.0% by weight orless.

Further, it is preferable that the electrically conductive film iscolorless and transparent, not inclined toward blue or greencharacteristic to an electrically conductive polymer, which is anobstacle for development for various purposes, or yellow characteristicto ITO. Therefore, it is preferable that a color tone of theelectrically conductive film is such that, in the Lab color systemstipulated JIS-Z-8722, an a value is −1.0 to 1.0, and a b value is −0.5to 5.0. When the a value is less than −1.0, green is stressed, and whenthe a value is more than 1.0, red is stressed. When the b value is lessthan −0.5, blue is stressed, and when the b value is more than 5.0,yellow is stressed.

Examples of a means to attain the aforementioned range of the color toneof the electrically conductive film include use of a bilayer CNT as aCNT, use of a CNT having a diameter of 50 nm or less, and acompositional weight rate of the CNT (A) in the electrically conductivelayer (the total of contents of (A), (B) and (C) in the electricallyconductive layer is let to be 100% by weight) of 40.0% by weight orless.

(Measuring method)

(1) Method of Determining CNT and Method of Confirming Diameter andAspect Ratio

In a method of determining a CNT species, its form was observed with ahigh resolution transmission electron microscope ((TEM) H-9000UHR(manufactured by Hitachi, Ltd.)) at a magnification of 100,000 to1,000,000, and a tube including one layer of a graphene sheet wasdefined as a monolayer CNT, a tube including two layers of graphenesheets was defined as a bilayer CNT, and a tube including three or morelayers of graphene sheets was defined as a multilayer CNT.

In addition, a tube in which a carbon skeleton having an angle relativeto a tube planar direction being changed by 30° or more is grown at anypart of the tube was defined as a bending-shaped CNT. Other tubes weredefined as straight-shaped CNTs. When a CNT has a structure other than a6-membered ring structure such as a 5-membered ring or 7-membered ringstructure in a carbon skeleton of the tube, the carbon skeleton may growwith an angle relative to a tube planar direction being changed by 30°or more in some cases (becoming a bending-shaped CNT in some cases). Inaddition, when a carbon skeleton of the tube has a honey comb structureonly of a 6-membered ring, the carbon skeleton grows linearly, becominga straight-shaped CNT.

Further, regarding the diameter and the aspect ratio, for example, uponobservation of a form of a CNT at a magnification of 500,000, arbitrary100 tubes were observed from a plurality of fields, the diameter and thetube length of each CNT were measured, and the aspect ratio wascalculated. Then, the averages of diameters and aspect ratios of 100tubes were calculated to obtain the final diameter and aspect ratio.

(2) Confirmation of CNT Network Structure in Electrically ConductiveLayer

A form of a surface of the electrically conductive film was observedwith a field emission scanning electron microscope ((FE-SEM) JIM-6700F(manufactured by JEOL Ltd.)) at a magnification of 500 to 100,000. Whena network structure is uniformly formed, the structure is observed asshown in FIG. 2.

(3) Thickness of Electrically Conductive Layer

The thickness of the electrically conductive layer was obtained bycalculation from the solid matter concentration of a CNT dispersion andthe nominal wet coating amount of a coater, letting the specific gravityof the CNT dispersion to be 1.0 g/cm³.

(4) Surface Specific Resistance Value

For measuring a surface specific resistance, the electrically conductivefilm is allowed to stand in the normal state (23° C., relative humidity65%) for 24 hours, and the resistance can be measured using High Star UP(manufactured by Mitsubishi Chemical Corporation, Model: MCP-HT450)based on JIS-K-6911 (1995 edition) under the same atmosphere. The numberof samples (A4 size: 21 cm×30 cm) to be measured regarding each exampleand comparative example was 1, measurement was performed once regardingeach of different five points on the samples, and the resulting averageof five points was defined as the surface specific resistance. When theelectrically conductive layer was laminated only on one side of thethermoplastic resin film, the surface on which the electricallyconductive layer was laminated was measured. On the other hand, when theelectrically conductive layers are laminated on both sides of thethermoplastic resin film, an average of five points measurement on oneside, and an average of five points measurement on the other side wereobtained, respectively, and the surface specific resistance for eachside was obtained.

(5) Total Light Transmittance

The total light transmittance was measured using a wholly automaticdirect reading haze computer “HGM-2DP” manufactured by Suga TestInstrument Co. Ltd. after the electrically conductive film was allowedto stand for 2 hours in the normal state (23° C., relative humidity65%). An average of three times of measurement was defined as the totallight transmittance of the electrically conductive film. In addition,when the electrically conductive layer was laminated only on one side ofa film, the electrically conductive film was disposed so that light wasintroduced only through the side on which the electrical conductivelayer was laminated.

(6) Adhesion Property/Abrasion Resistance Test of ElectricallyConductive Layer

To assess an adhesion property between the electrically conductive layerand the thermoplastic resin film and abrasion resistance of theelectrically conductive layer, a surface of the electrically conductivelayer was rubbed 50 times with a load of 200 g/mm² using a swab(manufactured by Johnson & Johnson, cotton 100%). Determination of theadhesion property/abrasion resistance was performed by observing achange in appearance visually.

Determination Criteria:

-   -   ∘: No change in appearance    -   x: Either of cutting or whitening of a coated film, and dropping        of a CNT (attachment of a CNT to a swab) is confirmed.

(7) Solvent Resistance Test

To assess solvent resistance of the electrically conductive layer, eachof various organic solvents (methanol, ethanol, isopropyl alcohol, ethylacetate, and hexane) was made to permeate into a swab (manufactured byJohnson & Johnson, cotton 100%), and a surface of the electricallyconductive layer was rubbed 50 times with a load of 200 g/mm².Determination of solvent resistance was performed by observing a changein appearance visually.

Determination Criteria:

-   -   ∘: No change in appearance    -   x: Either of cutting or whitening of a coated film, and dropping        of a CNT (attachment of a CNT to a swab) is confirmed.        (8) Change in Surface Specific Resistance Value after Rubbing        Treatment    -   (i) A surface resistance value A (Ω/□) of an electrically        conductive layer surface of the electrically conductive film was        obtained according to the method described in (4) “Surface        specific resistance value.”    -   (ii) An electrically conductive layer surface of the        electrically conductive film was subjected to a rubbing        treatment according to the rubbing method described in (6)        “Adhesion property/abrasion resistance test of electrically        conductive layer.” In addition, a surface resistance value B1        (Ω/□) of an electrically conductive layer surface which had been        subjected to a rubbing treatment of the electrically conductive        film was obtained according to the method described in (4)        “Surface specific resistance value.”    -   (iii) An electrically conductive layer surface of the        electrically conductive film was subjected to a rubbing        treatment according to the rubbing method described in (7)        “Solvent resistance test.” In addition, surface resistance        values B2 to B6 (Ω/□) of an electrically conductive layer        surface which had been subjected to a rubbing treatment of the        electrically conductive film were obtained according to the        method described in (4) “Surface specific resistance value.” B2        is a surface resistance value of the electrically conductive        film which had been subjected to a rubbing treatment after        permeating methanol into a swab. In addition, B3 is a surface        resistance value of the electrically conductive film which had        been subjected to a rubbing treatment after permeating ethanol        into a swab. In addition, B4 is a surface resistance value of        the electrically conductive film which had been subjected to a        rubbing treatment after permeating isopropyl alcohol into a        swab. In addition, B5 is a surface resistance value of the        electrically conductive film which had been subjected to a,        rubbing treatment after permeating ethyl acetate into a swab. In        addition, B6 is a surface resistance value of the electrically        conductive film which had been subjected to a rubbing treatment        after permeating hexane into a swab.    -   (iv) Bn (wherein n=1 to 6)/A was obtained and, when in all of        n=1 to 6, a relationship Bn/A≦10.0 is satisfied, the assessment        was ∘. On the other hand, when in any of n=1 to 6, a        relationship Bn/A≦10.0 is not satisfied, the assessment was x.

(9) Lab Color Tone Value

A color tone (a value, b value) of the electrically conductive film wasmeasured by a transmission method using a spectroscopic color differencemeter (SE-2000 manufactured by Nippon Denshoku Industries Co., Ltd.,light source: halogen lamp 12V4A, 0° to −45° post-spectroscopic system)based on JIS-Z-8722 (2000) in the normal state (23° C., relativehumidity 65%). For measurement, arbitrary five points of theelectrically conductive film were measured, and their average wasadopted.

EXAMPLES

Our films and processes will be explained further specifically based onexamples. However, the disclosure is not limited to those examples.

Example 1

A CNT dispersion was prepared as follows.

First, 1.0 mg of a CNT (straight bilayer CNT: manufactured by ScienceLaboratories, diameter 5 nm), 1.0 mg of carboxymethylcellulose sodium(Sigma-Aldrich Japan) (hereinafter, abbreviated as CMC-Na) as a CNTdispersant, and 248 mg of water were placed in a 50 mL sample tube, aCNT water dispersion was prepared, ultrasonic irradiation was performedfor 30 minutes using an ultrasonic grinder (VCX-502 manufactured byTokyo Rikakikai Co., Ltd., output 250 W, direct irradiation) to obtain auniform CNT water dispersion (CNT concentration 0.40 wt %, CNTdispersant 0.40 wt %, (B)/(A)=1.0).

Then, to this CNT water dispersion was added a thermosetting polyesterresin water dispersion (manufactured by Takamatsu Oil & Fat Co., Ltd.,PES resin A-120, solid matter concentration 25% by weight) as a binderresin, and the materials were mixed and stirred with a magnetic stirrerat 500 rpm for 15 minutes to obtain a CNT dispersion. Compositionalweight rates of a CNT (A), a CNT dispersant (B) and a binder resin (C)in the CNT dispersion (the total of contents of (A), (B) and (C) in theCNT dispersion is let to be 100% by weight) are as follows:

-   -   (A) 9.1% by weight    -   (B) 9.1% by weight    -   (C) 81.8% by weight.

Thereupon, a weight ration of (B)/(A) was 1.0.

Then, PET pellets (limiting viscosity 0.63 dl/g) substantiallycontaining no particles were sufficiently vacuum-dried, supplied to anextruder, melted at 285° C., extruded through a T-shaped spinneret intoa sheet, and wound on a mirror surface casting drum having a surfacetemperature of 25° C. using an electrostatic application casting method,followed by cooling and solidification. This unstretched film was heatedto 90° C., and stretched 3.4-fold in a longitudinal direction to obtaina monoaxially stretched film (B film). This film was subjected to acorona discharge treatment in the air.

Then, the CNT dispersion was applied to a corona dischargetreated-surface of the monoaxially stretched film using a bar coater.

Both ends in a width direction of the monoaxially stretched film appliedwith the CNT dispersion were grasped with a clip, and guided to apre-heating zone, the atmospheric temperature was adjusted to 75° C.,subsequently, the atmospheric temperature was adjusted to 110° C. usinga radiation heater and, then, the atmospheric temperature was adjustedto 90° C. to dry the CNT dispersion. Subsequently, the film wascontinuously stretched 3.5-fold in a width direction in a heating zone(stretching zone) at 120° C., subsequently, the film was heat-treatedfor 20 seconds in a heat treatment zone (thermal fixing zone) of 230° C.to obtain an electrically conductive film in which crystal orientationhad been completed.

In the resulting electrically conductive film, the thickness of the PETfilm was 125 p.m. In addition, an electrically conductive layer part wasobserved with an electron microscope and, as a result, it was confirmedthat a CNT finely dispersed in the electrically conductive layer formeda network structure randomly. Properties of the resulting electricallyconductive film are shown in the tables.

Example 2

According to the same manner as that of Example 1 except that additionamounts of the CNT, CMC-Na and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of the CNT (A), the CNT dispersant (B) and the binder resin(C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 3

According to the same manner as that of Example 1 except that additionamounts of the CNT, CMC-Na and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of the CNT (A), the CNT dispersant (B) and the binder resin(C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 4

According to the same manner as that of Example 1 except that additionamounts of the CNT, CMC-Na and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of the CNT (A), the CNT dispersant (B) and the binder resin(C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 5

According to the same manner as that of Example 1 except that additionamounts of the CNT, CMC-Na and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of the CNT (A), the CNT dispersant (B) and the binder resin(C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 6

According to the same manner as that of Example 1 except that additionamounts of the CNT, CMC-Na and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of the CNT (A), the CNT dispersant (B) and the binder resin(C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 7

According to the same manner as that of Example 1 except that additionamounts of the CNT, CMC-Na and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of the CNT (A), the CNT dispersant (B) and the binder resin(C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 8

According to the same manner as that of Example 1 except that additionamounts of the CNT, CMC-Na and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of the CNT (A), the CNT dispersant (B) and the binder resin(C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 9

According to the same manner as that of Example 1 except that additionamounts of the CNT, CMC-Na and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of the CNT (A), the CNT dispersant (B) and the binder resin(C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 10

According to the same manner as that of Example 1 except that additionamounts of the CNT, CMC-Na and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of the CNT (A), the CNT dispersant (B) and the binder resin(C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 11

According to the same manner as that of Example 1, a CNT dispersion wasobtained. Compositional weight rates of the CNT (A), the CNT dispersant(B) and the binder resin (C) in the CNT dispersion are shown in thetable.

According to the same manner as that of Example 1 except that thethickness of the electrically conductive layer was changed, using theCNT dispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 12

According to the same manner as that of Example 1 except that additionamounts of the CNT, CMC-Na and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of the CNT (A), the CNT dispersant (B) and the binder resin(C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 13

According to the same manner as that of Example 1 except that additionamounts of the CNT, CMC-Na and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of the CNT (A), the CNT dispersant (B) and the binder resin(C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 14

According to the same manner as that of Example 1 except that additionamounts of the CNT, CMC-Na and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of the CNT (A), the CNT dispersant (B) and the binder resin(C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 15

According to the same manner as that of Example 1 except that additionamounts of the CNT, CMC-Na and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of the CNT (A), the CNT dispersant (B) and the binder resin(C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 16

According to the same manner as that of Example 1 except that additionamounts of the CNT, CMC-Na and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of the CNT (A), the CNT dispersant (B) and the binder resin(C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 17

According to the same manner as that of Example 1 except that additionamounts of the CNT, CMC-Na and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of the CNT (A), the CNT dispersant (B) and the binder resin(C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 18

According to the same manner as that of Example 1 except that additionamounts of the CNT, CMC-Na and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of the CNT (A), the CNT dispersant (B) and the binder resin(C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 19

According to the same manner as that of Example 1 except that additionamounts of the CNT, CMC-Na and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of the CNT (A), the CNT dispersant (B) and the binder resin(C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 20

According to the same manner as that of Example 1 except that the CNTwas changed to a straight bilayer CNT (manufactured by ScienceLaboratories, diameter 3 nm), and addition amounts of the CNT, CMC-Naand the thermosetting polyester resin water dispersion were changed, aCNT dispersion was obtained. Compositional weight rates of the CNT (A),the CNT dispersant (B) and the binder resin (C) in the CNT dispersionare shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μM. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 21

According to the same manner as that of Example 1 except that the CNTwas changed to a straight bilayer CNT (manufactured by ScienceLaboratories, diameter 3 nm), and addition amounts of the CNT, CMC-Naand the thermosetting polyester resin water dispersion were changed, aCNT dispersion was obtained. Compositional weight rates of the CNT (A),the CNT dispersant (B) and the binder resin (C) in the CNT dispersionare shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 22

According to the same manner as that of Example 1 except that the CNTwas changed to a straight bilayer CNT (manufactured by ScienceLaboratories, diameter 3 nm), and addition amounts of the CNT, CMC-Naand the thermosetting polyester resin water dispersion were changed, aCNT dispersion was obtained. Compositional weight rates of the CNT (A),the CNT dispersant (B) and the binder resin (C) in the CNT dispersionare shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 23

According to the same manner as that of Example 1 except that the CNTwas changed to a straight bilayer CNT (manufactured by ScienceLaboratories, diameter 3 nm), and addition amounts of the CNT, CMC-Naand the thermosetting polyester resin water dispersion were changed, aCNT dispersion was obtained. Compositional weight rates of the CNT (A),the CNT dispersant (B) and the binder resin (C) in the CNT dispersionare shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 24

According to the same manner as that of Example 1 except that additionamounts of the CNT, CMC-Na and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of the CNT (A), the CNT dispersant (B) and the binder resin(C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 25

According to the same manner as that of Example 1 except that the CNTwas changed to a CNT which has three or more straight/bending mixedlayers (manufactured by Hyperion, diameter 15 nm), and addition amountsof the CNT, CMC-Na and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of the CNT (A), the CNT dispersant (B) and the binder resin(C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 26

According to the same manner as that of Example 1 except that the CNTwas changed to a CNT which has three or more straight/bending mixedlayers (manufactured by Showa Denko K.K., diameter 100 nm), and additionamounts of the CNT, CMC-Na and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of the CNT (A), the CNT dispersant (B) and the binder resin(C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 27

According to the same manner as that of Example 1 except that the CNTwas changed to a straight bilayer CNT (manufactured by ScienceLaboratories, diameter 3 nm), a CNT dispersion was obtained.Compositional weight rates of the CNT (A), the CNT dispersant (B) andthe binder resin (C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 28

According to the same manner as that of Example 1 except that the CNTwas changed to a straight bilayer CNT (manufactured by Microphase Co.,Ltd., diameter 10 nm), a CNT dispersion was obtained. Compositionalweight rates of the CNT (A), the CNT dispersant (B) and the binder resin(C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 29

According to the same manner as that of Example 1 except that 10.0 partsby weight of a petroleum wax as an organic easy sliding agent was addedrelative to the total of contents of (A), (B) and (C) in the CNTdispersion, of 90.0 parts by weight, a CNT dispersion was obtained.Compositional weight rates of the CNT (A), the CNT dispersant (B) andthe binder resin (C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 30

According to the same manner as that of Example 1 except that 5.0 partsby weight of a petroleum wax as an organic easy sliding agent was addedrelative to the total of contents of (A), (B) and (C) in the CNTdispersion, of 95.0 parts by weight, a CNT dispersion was obtained.Compositional weight rates of the CNT (A), the CNT dispersant (B) andthe binder resin (C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 31

First, a CNT dispersion was prepared. 1.0 mg of a CNT (straight/bendingmixed bilayer CNT: manufactured by Science Laboratories), 2.4 mg ofpolyvinylpyrrolidone (manufacture by Nippon Shokubai Co., Ltd., K-30)(hereinafter, abbreviated as PVP) as a CNT dispersant, and 120.5 mg ofwater were placed in a 50 mL sample tube, a CNT water dispersion wasprepared, and ultrasonic irradiation was performed for 30 minutes usingan ultrasonic grinding machine (VCX-502 manufactured by Tokyo RikakikaiCo., Ltd., output 250 W, direct irradiation) to obtain a uniform CNTdispersion (CNT concentration 0.83 wt %, CNT dispersant 2.0 wt %,(B)/(A)=2.4). To this CNT dispersion was added a thermosetting polyesterresin water dispersion (manufactured by Takamatsu Oil & Fat Co., Ltd.,PES resin A-120, 25%) as a binder resin, and the materials were mixedand stirred with a magnetic stirrer at 500 rpm for 15 minutes to obtaina CNT dispersion. Compositional weight rates of a CNT (A), a CNTdispersant (B) and a binder resin (C) in the CNT dispersion (the totalof contents of (A), (B) and (C) in the CNT dispersion is let to be 100%by weight) are as follows:

-   -   (A) 17.4% by weight    -   (B) 42.0% by weight    -   (C) 40.6% by weight.

Thereupon, a weight ratio of (B)/(A) was 2.4.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 32

According to the same manner as that of Example 31 except that additionamounts of the CNT, PVP and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of the CNT (A), the CNT dispersant (B) and the binder resin(C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 33

According to the same manner as that of Example 31 except that additionamounts of the CNT, PVP and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of the CNT (A), the CNT dispersant (B) and the binder resin(C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 34

According to the same manner as that of Example 31 except that additionamounts of the CNT, PVP and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of the CNT (A), the CNT dispersant (B) and the binder resin(C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 p.m. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 35

According to the same manner as that of Example 31 except that additionamounts of the CNT, PVP and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of the CNT (A), the CNT dispersant (B) and the binder resin(C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 36

According to the same manner as that of Example 31 except that additionamounts of the CNT, PVP and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of the CNT (A), the CNT dispersant (B) and the binder resin(C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 37

According to the same manner as that of Example 31 except that additionamounts of the CNT, PVP and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of the CNT (A), the CNT dispersant (B) and the binder resin(C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μM. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 38

According to the same manner as that of Example 31 except that additionamounts of the CNT, PVP and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of the CNT (A), the CNT dispersant (B) and the binder resin(C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 39

According to the same manner as that of Example 31 except that thebinder resin (C) was changed to a polyaniline water dispersion, andaddition amounts of the CNT, PVP and the polyaniline water dispersionwere changed, a CNT dispersion was obtained. Compositional weight ratesof the CNT (A), the CNT dispersant (B) and the binder resin (C) in theCNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Example 40

First, a CNT dispersion was prepared. 1.0 mg of a CNT (bilayer CNT:manufactured by Science Laboratories), 2.4 mg of sodiumpolystyrenesulfonate (manufactured by Tosoh Organic Chemical Co., Ltd.)(hereinafter, abbreviated as PSS) as a CNT dispersant, and 120.5 mg ofwater were placed in a 50 mL sample tube, a CNT water dispersion wasprepared, and ultrasonic irradiation was performed for 30 minutes usingan ultrasonic grinding machine (VCX-502 manufactured by Tokyo RikakikaiCo., Ltd., output 250 W, direct irradiation) to obtain a uniform CNTdispersion (CNT concentration 0.83 wt %, CNT dispersant 2.0 wt %,(B)/(A)=2.4). To this CNT dispersion was added a thermosetting polyesterresin water dispersion (manufactured by Takamatsu Oil & Fat Co., Ltd.,PES resin A-120, 25%) as a binder resin, and the materials were mixedand stirred with a magnetic stirrer at 500 rpm for 15 minutes to obtaina CNT dispersion. Compositional weight rates of CNT (A), a CNTdispersant (B) and a binder resin (C) in the CNT dispersion (the totalof contents of (A), (B) and (C) in the CNT dispersion is let to be 100%by weight) are as follows:

-   -   (A) 17.4% by weight    -   (B) 42.0% by weight    -   (C) 40.6% by weight.

Thereupon, a weight ratio of (B)/(A) was 2.4.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. Properties of the resulting electrically conductive film areshown in the tables.

Comparative Example 1

According to the same manner as that of Example 1 except that additionamounts of the CNT, CMC-Na and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion (CNT concentration 0.40 wt %,CNT dispersant 0.40 wt %, (B)/(A)=1.0) was obtained. This dispersion wasdiluted with water to adjust a CNT concentration to 0.06 wt %, to obtaina CNT dispersion. Compositional weight rates of a CNT (A), a CNTdispersant (B) and a binder resin (C) in the CNT dispersion (the totalof contents of (A), (B) and (C) in the CNT dispersion is let to be 100%by weight) are as shown in the tables.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. However, since the binder resin is not present in theelectrically conductive layer, when adhesion property/abrasionresistance of the electrically conductive layer were tried to beassessed, the electrically conductive layer peeled off the PET film.Other properties of the resulting electrically conductive film are shownin the tables.

Comparative Example 2

A mixed solution of a CNT dispersant and a binder resin was prepared asfollows.

1.0 mg of CMC-Na and 248 mg of water were placed in a 50 mL sample tube,a thermosetting polyester resin water dispersion (manufactured byTakamatsu Oil & Fat Co., Ltd., PES resin A-120, solid matterconcentration 25% by weight) as a binder resin was added, and thematerials were mixed and stirred with a magnetic stirrer at 500 rpm for15 minutes to obtain a mixed solution. Compositional weight rates of aCNT (A), a CNT dispersant (B) and a binder resin (C) in the mixedsolution (the total of contents of (A), (B) and (C) in the mixedsolution is let to be 100% by weight) are as shown in the table.

According to the same manner as that of Example 1 and using the mixedsolution, an electrically conductive film was obtained. In the resultingelectrically conductive film, the thickness of a PET film was 125 μm. Acoated film part was observed with an electron microscope and, as aresult, formation of a uniform coated film in which no CNT was presentwas confirmed. In addition, properties of the resulting film are shownin the tables, and since no CNT was present, consequently, electricalconductivity was very poor.

Comparative Example 3

According to the same manner as that of Example 1, it was tried to makea uniform CNT dispersion, so that compositional weight rates of a CNT(A) and a binder resin (C) (total of contents of (A), (B) and (C) in theCNT dispersion is let to be 100% by weight) became the rates shown inthe table, by changing the addition amounts of the CNT, CMC-Na and thethermosetting polyester resin water dispersion were changed, but sincethe CNT dispersant (B) was not added, the CNT was not dispersed and wasseparated from water, and a CNT dispersion could not be made.

Comparative Example 4

According to the same manner as that of Example 1 except that additionamounts of the CNT, CMC-Na and the thermosetting polyester resin waterdispersion were changed, a uniform CNT dispersion (CNT concentration0.40 wt %, CNT dispersant 8.0 wt %, (B)/(A)=20.0) was obtained. Further,the thermosetting polyester resin water dispersion was similarly mixed,and the mixture was stirred to prepare a CNT dispersion. Compositionalweight rates of a CNT (A), a CNT dispersant (B) and a binder resin (C)in the CNT dispersion (the total of contents of (A), (B) and (C) in theCNT dispersion is let to be 100% by weight) are as shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μM. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly, but electrical conductivity was poor. In addition, otherproperties of the resulting electrically conductive film are shown inthe tables.

Comparative Example 5

According to the same manner as that of Example 1 except that additionamounts of the CNT, CMC-Na and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of a CNT (A), a CNT dispersant (B) and a binder resin (C)in the CNT dispersion (the total of contents of (A), (B) and (C) in theCNT dispersion is let to be 100% by weight) are as shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly, but electrical conductivity was poor. In addition, otherproperties of the resulting electrically conductive film are shown inthe tables.

Comparative Example 6

According to the same manner as that of Example 1 except that additionamounts of the CNT, CMC-Na and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion ((B)/(A)=0.25) was prepared sothat compositional weight rates as shown in the table were obtained, butaggregation of the CNT was confirmed from immediately after dispersing,and the CNT was aggregated and settled in the solution. As a result, aCNT dispersion could not be obtained.

Comparative Example 7

According to the same manner as that of Example 1 except that 12.0 partsby weight of a petroleum wax as an organic easy sliding agent was addedrelative to the total of contents of (A), (B) and (C) in the CNTdispersion, of 88.0 parts by weight, a CNT dispersion was obtained.Compositional weight rates of the CNT (A), the CNT dispersant (B), andthe binder resin (C) in the CNT dispersion are shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly, but electrical conductivity was poor. Properties of theresulting electrically conductive film are shown in the tables.

Comparative Example 8

According to the same manner as that of Example 1 except that additionamounts of the CNT, CMC-Na and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of a CNT (A), a CNT dispersant (B) and a binder resin (C)in the CNT dispersion (the total of contents of (A), (B) and (C) in theCNT dispersion is let to be 100% by weight) are as shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. However, since the CNT was present in the electricallyconductive layer in a large amount, when adhesion property/abrasionresistance of the electrically conductive layer were tried to beassessed, an extra CNT in the electrically conductive layer waspartially peeled off the PET film. Other properties of the resultingelectrically conductive film are shown in the tables.

Comparative Example 9

According to the same manner as that of Example 1 except that additionamounts of the CNT, CMC-Na and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of a CNT (A), a CNT dispersant (B) and a binder resin (C)in the CNT dispersion (the total of contents of (A), (B) and (C) in theCNT dispersion is let to be 100% by weight) are as shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm, An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. However, since the amount of a binder resin present in theelectrically conductive layer is small, when adhesion property/abrasionresistance of the electrically conductive layer were tried to beassessed, the electrically conductive layer was partially peeled off thePET film. Other properties of the resulting electrically conductive filmare shown in the tables.

Comparative Example 10

According to the same manner as that of Example 1 except that additionamounts of the CNT, CMC-Na and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion ((B)/(A)=0.4) was prepared sothat compositional weight rates as shown in the table were obtained, butaggregation of the CNT was confirmed from immediately after dispersing,and the CNT was aggregated and settled in the solution. As a result, aCNT dispersion could not be obtained.

Comparative Example 11

According to the same manner as that of Example 31 except that additionamounts of the CNT, PVP and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of a CNT (A), a CNT dispersant (B) and a binder resin (C)in the CNT dispersion (the total of contents of (A), (B) and (C) in theCNT dispersion is let to be 100% by weight) are as shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. However, since a binder resin is not present in theelectrically conductive layer, when adhesion property/abrasionresistance of the electrically conductive layer were tried to beassessed, the electrically conductive layer peeled off the PET film.Other properties of the resulting electrically conductive film are shownin the tables.

Comparative Example 12

According to the same manner as that of Example 31 except that additionamounts of the CNT, PVP and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of a CNT (A), a CNT dispersant (B) and a binder resin (C)in the CNT dispersion (the total of contents of (A), (B) and (C) in theCNT dispersion is let to be 100% by weight) are as shown in the tables.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. However, since the amount of the CNT present in theelectrically conductive layer is small, electrical conductivity waspoor. In addition, the CNT dispersant was excessive relative to the CNT,the electrically conductive layer was whitened, and when adhesionproperty/abrasion resistance of the electrically conductive layer weretried to be assessed, the electrically conductive layer peeled off thePET film. Other properties of the resulting electrically conductive filmare shown in the tables.

Comparative Example 13

According to the same manner as that of Example 1 except that additionamounts of the CNT, CMC-Na and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion ((B)/(A)=0.3) was prepared sothat compositional weight rates as shown in the table were obtained, butaggregation of the CNT was confirmed from immediately after dispersing,and the CNT was aggregated and settled in the solution. As a result, aCNT dispersion could not be obtained.

Comparative Example 14

According to the same manner as that of Example 31 except that additionamounts of the CNT, PVP and the thermosetting polyester resin waterdispersion were changed, a CNT dispersion was obtained. Compositionalweight rates of a CNT (A), a CNT dispersant (B) and a binder resin (C)in the CNT dispersion (the total of contents of (A), (B) and (C) in theCNT dispersion is let to be 100% by weight) are as shown in the table.

According to the same manner as that of Example 1 and using the CNTdispersion, an electrically conductive film was obtained. In theresulting electrically conductive film, the thickness of a PET film was125 μm. An electrically conductive layer part was observed with anelectron microscope and, as a result, it was confirmed that a CNT finelydispersed in an electrically conductive layer formed a network structurerandomly. In addition, the CNT dispersant was excessive relative to theCNT, the electrically conductive layer was whitened, and when adhesionproperty/abrasion resistance of the electrically conductive layer weretried to be assessed, the electrically conductive layer peeled off thePET film. Other properties of the resulting electrically conductive filmare shown in the tables.

In addition, the aspect ratios of the CNTs used in examples/comparativeexamples are 100 or more in all cases except for Example 26.

TABLE 1 Compositional weight rate of each Total of contents component inelectrically Weight of (A), (B) and Thickness of conductive layer (CNTratio of (C) relative to entire Number CNT electrically dispersion) (%by weight)* (B)/(A) electrically conductive CNT of CNT diameterconductive (A) (B) (C) (—) layer (% by weight) species layers (nm) layer(nm) Example 1 9.1 9.1 81.8 1.0 100.0 Straight Bilayer 5.0 40 Example 216.7 16.7 66.6 1.0 100.0 Straight Bilayer 5.0 40 Example 3 40.0 40.020.0 1.0 100.0 Straight Bilayer 5.0 15 Example 4 5.0 50.0 45.0 10.0100.0 Straight Bilayer 5.0 40 Example 5 1.0 0.5 98.5 0.5 100.0 StraightBilayer 5.0 200 Example 6 1.0 15.0 84.0 15.0 100.0 Straight Bilayer 5.040 Example 7 40.0 20.0 40.0 0.5 100.0 Straight Bilayer 5.0 40 Example 840.0 56.0 4.0 1.4 100.0 Straight Bilayer 5.0 40 Example 9 6.0 90.0 4.015.0 100.0 Straight Bilayer 5.0 80 Example 10 40.0 40.0 20.0 1.0 100.0Straight Bilayer 5.0 80 Example 11 9.1 9.1 81.8 1.0 100.0 StraightBilayer 5.0 20 Example 12 8.0 4.0 88.0 0.5 100.0 Straight Bilayer 5.0 40Example 13 8.0 16.0 76.0 2.0 100.0 Straight Bilayer 5.0 40 Example 1410.0 5.0 85.0 0.5 100.0 Straight Bilayer 5.0 40 Example 15 10.0 20.070.0 2.0 100.0 Straight Bilayer 5.0 40 *Total of contents of (A), (B)and (C) in electrically conductive layer (CNT dispersion) is let to be100% by weight.

TABLE 2 Compositional weight rate of each Total of contents component inelectrically Weight of (A), (B) and Thickness of conductive layer (CNTratio of (C) relative to entire Number CNT electrically dispersion) (%by weight)* (B)/(A) electrically conductive CNT of CNT diameterconductive (A) (B) (C) (—) layer (% by weight) species layers (nm) layer(nm) Example 16 6.0 3.0 91.0 0.5 100.0 Straight Bilayer 5.0 40 Example17 6.0 24.0 70.0 4.0 100.0 Straight Bilayer 5.0 40 Example 18 12.0 6.091.0 0.5 100.0 Straight Bilayer 5.0 40 Example 19 12.0 48.0 40.0 4.0100.0 Straight Bilayer 5.0 40 Example 20 30.0 15.0 55.0 0.5 100.0Straight Bilayer 3.0 20 Example 21 30.0 56.0 14.0 1.9 100.0 StraightBilayer 3.0 20 Example 22 40.0 20.0 40.0 0.5 100.0 Straight Bilayer 3.020 Example 23 40.0 56.0 4.0 1.4 100.0 Straight Bilayer 3.0 20 Example 248.0 8.0 84.0 1.0 100.0 Straight Bilayer 5.0 40 Example 25 8.0 8.0 84.01.0 100.0 Straight/ 3 or 15.0 40 bending more mixture layers Example 268.0 8.0 84.0 1.0 100.0 Straight/ 3 or 100.0 40 bending more mixturelayers Example 27 9.1 9.1 81.8 1.0 100.0 Straight Bilayer 3.0 40 Example28 9.1 9.1 81.8 1.0 100.0 Straight Bilayer 10.0 40 *Total of contents of(A), (B) and (C) in electrically conductive layer (CNT dispersion) islet to be 100% by weight.

TABLE 3 Compositional weight rate of each Total of contents component inelectrically Weight of (A), (B) and Thickness of conductive layer (CNTratio of (C) relative to entire Number CNT electrically dispersion) (%by weight)* (B)/(A) electrically conductive CNT of CNT diameterconductive (A) (B) (C) (—) layer (% by weight) species layers (nm) layer(nm) Example 31 17.4 42.0 40.6 2.4 100.0 Straight/ Bilayer 5.0 40bending mixture Example 32 13.5 32.4 54.1 2.4 100.0 Straight/ Bilayer5.0 40 bending mixture Example 33 8.1 19.4 72.5 2.4 100.0 Straight/Bilayer 5.0 40 bending mixture Example 34 13.5 32.4 54.1 2.4 100.0Straight/ Bilayer 5.0 100 bending mixture Example 35 13.5 32.4 54.1 2.4100.0 Straight/ Bilayer 5.0 480 bending mixture Example 36 5.0 50.0 45.010.0 100.0 Straight/ Bilayer 5.0 40 bending mixture Example 37 2.8 6.790.5 2.4 100.0 Straight/ Bilayer 5.0 280 bending mixture Example 38 36.454.5 9.1 1.5 100.0 Straight/ Bilayer 5.0 15 bending mixture Example 399.1 30.3 60.6 3.3 100.0 Straight/ Bilayer 5.0 70 bending mixture Example40 17.4 42.0 40.6 2.4 100.0 Straight Bilayer 5.0 40 *Total of contentsof (A), (B) and (C) in electrically conductive layer (CNT dispersion) islet to be 100% by weight.

TABLE 4 Compositional weight rate of each Total of contents component inelectrically Weight of (A), (B) and Thickness of conductive layer (CNTratio of (C) relative to entire Number CNT electrically dispersion) (%by weight)* (B)/(A) electrically conductive CNT of CNT diameterconductive (A) (B) (C) (—) layer (% by weight) species layers (nm) layer(nm) Comparative 50.0 50.0 0.0 1.0 100.0 Straight Bilayer 5.0 2 Example1 Comparative 0.0 50.0 50.0 — 100.0 — — — 40 Example 2 Comparative 50.00.0 50.0 0.0 100.0 Straight Bilayer 5.0 — Example 3 Comparative 3.3 66.030.7 20.0 100.0 Straight Bilayer 5.0 40 Example 4 Comparative 0.9 13.585.6 15.0 100.0 Straight Bilayer 5.0 40 Example 5 Comparative 1.0 0.398.7 0.3 100.0 Straight Bilayer 5.0 — Example 6 Comparative 40.1 40.119.8 1.0 100.0 Straight Bilayer 5.0 40 Example 8 Comparative 30.0 66.13.9 2.2 100.0 Straight Bilayer 5.0 40 Example 9 Comparative 30.0 12.058.0 0.4 100.0 Straight Bilayer 5.0 — Example 10 Comparative 29.3 70.70.0 2.4 100.0 Straight/ Bilayer 5.0 2 Example 11 bending mixtureComparative 3.3 66.0 30.7 20.0 Straight/ Bilayer 5.0 40 Example 12bending mixture Comparative 0.3 0.1 99.6 0.3 Straight/ Bilayer 5.0 —Example 13 bending mixture Comparative 4.5 90.0 5.5 20.0 Straight/Bilayer 5.0 40 Example 14 bending mixture *Total of contents of (A), (B)and (C) in electrically conductive layer (CNT dispersion) is let to be100% by weight.

TABLE 5 Compositional weight rate of each component in electricallyTotal of contents conductive layer (CNT Weight of (A), (B) and Contentof petroleum dispersion) (part by weight) ratio of (C) relative toentire wax relative to entire Petroleum (B)/(A) electrically conductiveelectrically conductive (A) (B) (C) wax (—) layer (% by weight) layer (%by weight) Example 29 8.19 8.19 73.62 10.0 1.0 90.0 10.0 Example 308.645 8.645 77.71 5.0 1.0 95.0 5.0 Comparative 8.008 8.008 71.984 12.01.0 88.0 12.0 Example 7

TABLE 6 Compositional weight rate of Total of contents each component inelectrically Weight of (A), (B) and Thickness of conductive layer (CNTratio of (C) relative to entire Number CNT electrically dispersion) (%by weight)* (B)/(A) electrically conductive CNT of CNT diameterconductive (A) (B) (C) (—) layer (% by weight) species layers (nm) layer(nm) Example 29 9.1 9.1 81.8 1.0 90.0 Straight Bilayer 5.0 40 Example 309.1 9.1 81.8 1.0 95.0 Straight Bilayer 5.0 40 Comparative 9.1 9.1 81.81.0 88.0 Straight Bilayer 5.0 40 Example 7 *Total of contents of (A),(B) and (C) in electrically conductive layer (CNT dispersion) is let tobe 100% by weight.

TABLE 7 Adhesion Change in Surface Total property/abrasion surfacespecific specific light resistance of resistance resistance trans-electrically Solvent resistance value after Color tone value mittanceconductive Isopropyl Ethyl rubbing a b (Ω/□) (%) layer Methanol Ethanolalcohol acetate Hexane treatment value value Example 1 3.0 × 10⁷ 86 ◯ ◯◯ ◯ ◯ ◯ ◯ −0.2 2.2 Example 2 1.0 × 10⁷ 82 ◯ ◯ ◯ ◯ ◯ ◯ ◯ −0.2 2.6 Example3 3.0 × 10⁷ 85 ◯ ◯ ◯ ◯ ◯ ◯ ◯ −0.4 3.2 Example 4 1.0 × 10⁹ 87 ◯ ◯ ◯ ◯ ◯ ◯◯ −0.1 2.3 Example 5 5.0 × 10⁹ 85 ◯ ◯ ◯ ◯ ◯ ◯ ◯ −0.3 1.7 Example 6  1.0× 10¹⁰ 88 ◯ ◯ ◯ ◯ ◯ ◯ ◯ −0.1 1.5 Example 7 1.5 × 10⁵ 80 ◯ ◯ ◯ ◯ ◯ ◯ ◯−0.1 3.6 Example 8 3.0 × 10⁵ 80 ◯ ◯ ◯ ◯ ◯ ◯ ◯ −0.1 3.1 Example 9 6.0 ×10⁸ 85 ◯ ◯ ◯ ◯ ◯ ◯ ◯ −0.1 2.0 Example 10 4.0 × 10⁴ 68 ◯ ◯ ◯ ◯ ◯ ◯ ◯ −0.24.0 Example 11 2.0 × 10⁹ 87 ◯ ◯ ◯ ◯ ◯ ◯ ◯ −0.3 2.5 Example 12 5.0 × 10⁷86 ◯ ◯ ◯ ◯ ◯ ◯ ◯ −0.2 2.2 Example 13 5.0 × 10⁷ 86 ◯ ◯ ◯ ◯ ◯ ◯ ◯ −0.2 2.2Example 14 3.0 × 10⁷ 85 ◯ ◯ ◯ ◯ ◯ ◯ ◯ −0.2 2.3 Example 15 2.0 × 10⁷ 85 ◯◯ ◯ ◯ ◯ ◯ ◯ −0.2 2.3 Example 16 6.0 × 10⁸ 86 ◯ ◯ ◯ ◯ ◯ ◯ ◯ −0.1 2.1Example 17 5.0 × 10⁸ 86 ◯ ◯ ◯ ◯ ◯ ◯ ◯ −0.1 2.1 Example 18 2.0 × 10⁷ 84 ◯◯ ◯ ◯ ◯ ◯ ◯ −0.2 2.6 Example 19 1.0 × 10⁷ 84 ◯ ◯ ◯ ◯ ◯ ◯ ◯ −0.2 2.6

TABLE 8 Adhesion Change in Surface Total property/abrasion surfacespecific specific light resistance of resistance resistance trans-electrically Solvent resistance value after Color tone value mittanceconductive Isopropyl Ethyl rubbing a b (Ω/□) (%) layer Methanol Ethanolalcohol acetate Hexane treatment value value Example 20 3000 83 ◯ ◯ ◯ ◯◯ ◯ ◯ −0.1 3.0 Example 21 2500 83 ◯ ◯ ◯ ◯ ◯ ◯ ◯ −0.1 3.0 Example 22 100081 ◯ ◯ ◯ ◯ ◯ ◯ ◯ −0.1 3.2 Example 23  800 81 ◯ ◯ ◯ ◯ ◯ ◯ ◯ −0.1 3.2Example 24 4.0 × 10⁷ 86 ◯ ◯ ◯ ◯ ◯ ◯ ◯ −0.2 2.2 Example 25  5.0 × 10¹⁰ 78◯ ◯ ◯ ◯ ◯ ◯ ◯ −0.1 4.0 Example 26  5.0 × 10¹² 68 X X X X X X X −0.1 5.2Example 27 1.0 × 10⁷ 86 ◯ ◯ ◯ ◯ ◯ ◯ ◯ −0.2 2.2 Example 28 6.0 × 10⁷ 86 ◯◯ ◯ ◯ ◯ ◯ ◯ −0.2 2.2 Example 29 6.0 × 10⁷ 86 ◯ ◯ ◯ ◯ ◯ ◯ ◯ −0.2 2.2Example 30 4.0 × 10⁷ 86 ◯ ◯ ◯ ◯ ◯ ◯ ◯ −0.2 2.2 Example 31 3.0 × 10⁴ 80 ◯X X X X X X −0.2 2.5 Example 32 1.0 × 10⁶ 83 ◯ X X X X X X −0.2 2.3Example 33 3.0 × 10⁷ 85 ◯ X X X X X X −0.2 2.2 Example 34 2.5 × 10⁷ 78 ◯X X X X ◯ X −0.1 2.7 Example 35 6.2 × 10⁶ 60 ◯ X X X ◯ ◯ X −0.1 0.5Example 36 1.0 × 10⁹ 86 ◯ X X X X X X −0.2 2.1 Example 37 5.0 × 10⁹ 83 ◯X X X X ◯ X −0.2 2.0 Example 38 3.0 × 10⁴ 82 ◯ X X X X X X −0.4 3.1

TABLE 9 Adhesion Change in Surface Total property/abrasion surfacespecific specific light resistance of resistance resistance trans-electrically Solvent resistance value after Color tone value mittanceconductive Isopropyl Ethyl rubbing a b (Ω/□) (%) layer Methanol Ethanolalcohol acetate Hexane treatment value value Example 39 1.2 × 10¹⁰ 92 ◯X X X X X X −3.0 2.5 Example 40 3.0 × 10⁴  80 ◯ X X X X X X −0.2 2.5Comparative 1.0 × 10⁷  87 X X X X X X X −0.1 4.0 Example 1 Comparative3.0 × 10¹⁵ 91 ◯ ◯ ◯ ◯ ◯ ◯ ◯ −0.1 0.9 Example 2 Comparative — — —(Electrically conductive layer cannot — — — Example 3 be formed due toinability Comparative 1.0 × 10¹³ 85 ◯ ◯ ◯ ◯ ◯ ◯ ◯ −0.1 2.0 Example 4Comparative 5.0 × 10¹² 89 ◯ ◯ ◯ ◯ ◯ ◯ ◯ −0.1 4.9 Example 5 Comparative —— — (Electrically conductive layer cannot — — — Example 6 be formed dueto inability Comparative 2.0 × 10¹⁰ 86 ◯ X X X X X X −0.2 2.2 Example 7Comparative 2.0 × 10⁵  78 X X X X X X X −0.3 3.0 Example 8 Comparative8.0 × 10⁵  79 X X X X X X X −0.3 3.0 Example 9 Comparative — — —(Electrically conductive layer cannot — — — Example 10 be formed due toinability Comparative 1.0 × 10⁷  87 X X X X X X X −0.1 2.0 Example 11Comparative 3.0 × 10¹³ 85 X X X X X X X −0.1 2.0 Example 12 Comparative— — — (Electrically conductive layer cannot — — — Example 13 be formeddue to inability Comparative 2.0 × 10⁶  82 X X X X X X X −0.1 2.1Example 14

INDUSTRIAL APPLICABILITY

We provide an electrically conductive film having a transparentelectrically conductive layer which can be manufactured by applying aCNT dispersion to a thermoplastic resin film, and the electricallyconductive film can be used for an electrostatic film, a touch panel, atransparent electrode as a substitute for ITO, or the like.

What is claimed is:
 1. An electrically conductive film having anelectrically conductive layer on at least one side, which is athermoplastic resin film in which the electrically conductive layercontains a carbon nanotube (A), a carbon nanotube dispersant (B)comprising carboxy methylcellulose sodium and a binder resin (C),wherein the total contents of (A), (B) and (C) in the electricallyconductive layer is 90% by weight or more relative to the entireelectrically conductive layer, weight rates of (A), (B) and (C) are (A)1.0 to 40.0% by weight, (B) 0.5 to 90.0% by weight, and (C) 4.0 to 98.5%by weight, respectively, and a weight ratio of (B) and (A) ((B)/(A)) is0.5 or more and 15.0 or less: wherein total of contents of (A), (B) and(C) is 100% by weight.
 2. The electrically conductive film according toclaim 1, wherein the carbon nanotube dispersant (B) further comprises atleast one selected from the group consisting of a polystyrene sulfonatesalt, a polyvinylpyrrolidone-based polymer, water-soluble cellulose anda water-soluble cellulose derivative.
 3. The electrically conductivefilm according to claim 1, wherein the binder resin (C) is at least oneselected from the group consisting of a polyester resin and a melamineresin.
 4. The electrically conductive film according to claim 1, whereinthe carbon nanotube (A) is at least one selected from the groupconsisting of a straight or bending-shaped monolayer carbon nanotube, astraight or bending-shaped bilayer carbon nanotube, and a straight orbending-shaped multilayer carbon nanotube.
 5. The electricallyconductive film according to claim 1, wherein the carbon nanotube (A)has a diameter of 50 nm or less and/or an aspect ratio of 100 or more.6. The electrically conductive film according to claim 1, wherein asurface resistance value A (Ω/□) of an electrically conductive layersurface is 1.0×10¹⁰Ω/□ or less, and a surface resistance value B (Ω/□)of the electrically conductive layer surface after a rubbing treatmentsatisfies:B/A≦10.0.
 7. The electrically conductive film according to claim 1,wherein an a value of the Lab color system satisfies −1.0 to 1.0, and ab value satisfies −0.5 to 5.0.
 8. The electrically conductive filmaccording to claim 2, wherein the binder resin (C) is at least oneselected from the group consisting of a polyester resin and a melamineresin.
 9. The electrically conductive film according to claim 2, whereinthe carbon nanotube (A) is at least one selected from the groupconsisting of a straight or bending-shaped monolayer carbon nanotube, astraight or bending-shaped bilayer carbon nanotube, and a straight orbending-shaped multilayer carbon nanotube.
 10. The electricallyconductive film according to claim 3, wherein the carbon nanotube (A) isat least one selected from the group consisting of a straight orbending-shaped monolayer carbon nanotube, a straight or bending-shapedbilayer carbon nanotube, and a straight or bending-shaped multilayercarbon nanotube.
 11. The electrically conductive film according to claim2, wherein the carbon nanotube (A) has a diameter of 50 nm or lessand/or an aspect ratio of 100 or more.
 12. The electrically conductivefilm according to claim 3, wherein the carbon nanotube (A) has adiameter of 50 nm or less and/or an aspect ratio of 100 or more.
 13. Theelectrically conductive film according to claim 4, wherein the carbonnanotube (A) has a diameter of 50 nm or less and/or an aspect ratio of100 or more.
 14. The electrically conductive film according to claim 2,wherein a surface resistance value A (Ω/□) of an electrically conductivelayer surface is 1.0×10¹⁰Ω/□ or less, and a surface resistance value B(Ω/□) of the electrically conductive layer surface after a rubbingtreatment satisfies:B/A≦10.0.
 15. The electrically conductive film according to claim 3,wherein a surface resistance value A (Ω/□) of an electrically conductivelayer surface is 1.0×10¹⁰Ω/□ or less, and a surface resistance value B(Ω/□) of the electrically conductive layer surface after a rubbingtreatment satisfies:B/A≦10.0.
 16. The electrically conductive film according to claim 4,wherein a surface resistance value A (Ω/□) of an electrically conductivelayer surface is 1.0×10¹⁰Ω/□ or less, and a surface resistance value B(Ω/□) of the electrically conductive layer surface after a rubbingtreatment satisfies:B/A≦10.0.
 17. The electrically conductive film according to claim 5,wherein a surface resistance value A (Ω/□) of an electrically conductivelayer surface is 1.0×10¹⁰Ω/□ or less, and a surface resistance value B(Ω/□) of the electrically conductive layer surface after a rubbingtreatment satisfies:B/A≦10.0.
 18. The electrically conductive film according to claim 2,wherein an a value of the Lab color system satisfies −1.0 to 1.0, and ab value satisfies −0.5 to 5.0.
 19. The electrically conductive filmaccording to claim 3, wherein an a value of the Lab color systemsatisfies −1.0 to 1.0, and a b value satisfies −0.5 to 5.0.